Almost since the first development and use of mobile vehicles, theft and unauthorized use of such vehicles has been a serious concern to owners of the vehicles. Various different devices and systems have been heretofore proposed to combat the theft and unauthorized use problem. Generally, the object of the particular anti-theft device is to disable the engine of the motor vehicle and/or to produce an audible alarm to deter unauthorized users from utilizing the motor vehicle. Many of such systems require that the user enter a pre-set coded signal which either disengages the disabling device or prevents it from disabling the electrical system which it is designed to disable.
Some anti-theft systems utilize radio signals to activate or deactivate a mobile vehicle electrical system. U.S. Pat. No. 4,023,138 discloses a vehicle theft-prevention system which includes a receiver located in the vehicle which receives a signal from a remote transmitter. When the distance between the receiver and transmitter exceeds a predetermined amount such that the signal's strength at the receiver is less than a predetermined signal level, a control circuit is actuated which, upon actuation, may actuate an alarm and deactivate the vehicle ignition system so as to prevent further operation of the vehicle or both.
U.S. Pat. No. 4,413,261 discloses a coded control system for a vehicle ignition system which uses a self-contained radio transmitter unit for broadcasting a coded signal to a receiver/controller unit on the vehicle which is wired into the vehicle's engine ignition circuit.
Another security and anti-theft system discloses an apparatus for preventing theft or unauthorized use of an article such as a motor vehicle and prevents normal operation of the article unless electrical communication has been established between an exposed conductive element and a touch pole. That disclosure is made in U.S. Pat. No. 4,507,644. The disabling mechanism in this disclosure does not require the use of a coded signal to disengage the disabling system.
In recent years, increasing numbers of mobile vehicles have become equipped with cellular mobile telephones. Other electronic devices are also being added to mobile vehicles as additional tools for the traveling business person and as a convenience for the ordinary traveler. Prior to the subject invention hereinafter described, a security and anti-theft system has not been combined with and commonly controlled through a cellular mobile telephone by the disclosed means.